What the Monkeys told us

During my six years in the Madre de Dios region f the Peruvian Amazon, I learned to listen for the soft twitter that meant a family of bald-faced sakis was nearby. With my team of graduate students, local woodsmen, and former – hunters – turned – conservationists, I spent thousands of hours watching and waiting for the surprisingly hairy little monkeys to appear, only to have them vanish after a fleeting glimpse.

But watch and wait we did, because we knew that learning about eating habits and distribution patterns of this “umbrella species” – along with those of several other far – ranging species such jaguars, pumas, macaws and white – lipped peccaries – would give us the information we needed to determine how much and what type of land should be protected in this slice of the Amazon.

Geneticists tell us that at least 2 000 individuals must live in a species’ population in order for that species to be safely conserved in perpetuity.

The science of conservation planning requires identifying which kinds of habitat are necessary and how to integrate them into large enough areas to protect the maximum number of species. Since we clearly can’t study all of the myriad species that live in any one section of the Amazon, we selected those suspected of being the most area-sensitive, with the assumption that protecting critical habitat for these species would likewise protect areas critical to hundreds more.

Unlike the other species we selected, however, the sakis, which we came to regard as the “phantoms of the jungle”, could not be capture and fitted with GPS – adapted collars to help us track their movements. To learn about this species, so rarely observed by humans because of their talent for instantaneously disappearing into the landscape, we had to help them habituate to us, by quietly observing them for as long as they would allow it.

It took months, but eventually we learned a few things about the sakis that helped us to understand their habitat needs. We found, for example, that unlike other monkeys, this rare species does not eat ripened fruit, but prefers the seeds of immature fruit. We also learned that, unlike other monkeys, the saki does not come crashing through the trees but quietly slips from branch to branch, travelling in small families of five or six, rather than larger groups.

That means they need to live in dense, mature forested areas where the branches are close enough together for them to travel without making much noise.

Tracking the other species, though relatively simpler, likewise taught us some things that surprised us. For example, by capturing and collaring jaguars and pumas, we learned that these big cats behave quite differently from each other. Big cats are believed to be territorial, with individual males claiming an area exclusively. This we found to be true of the pumas we tracked, but the male jaguars overlapped territories quite comfortably.

We were likewise surprised to see that both jaguars and pumas, previously assumed to live scattered throughout the jungle, preferred to forage along the riverbeds. These findings indicate that protecting this species will require securing large expanses of river area.

Like the big cats, peccaries – pig- like animals that live in groups of up to 1 000 and are a key source of food for the Amur Indians – also prefer to feed in the food plains of larger rivers. There the find the palm nuts they depend on for sustenance. Because the palm trees are widely scattered except in floodplains, the peccaries must travel from river to river, often covering 30 to 40 miles in search of a new feeding area.

Macaws, we learned, also travel great distance – up to 100 miles – when not nesting. The team captured and tagged these amazing birds by erecting scaffolding up to 100 feet high in order to reach their nests.

We’ll now compile all of these data into an assessment to determine how much area we believed needs to be protected, and how much of each particular habitat. Clearly, the area will be large – likely millions of acres. An immediate concern arises from this conclusion because most individual national parks and protected areas are considerably smaller than this total. We will need to ensure that there is sufficient connectivity between parks and reserves to allow these species to maintain large enough populations.

I came to reorganize the importance of this kind information decades ago, when I was doing my graduate work in Costa Rica studying the habit of the quetzal, a strikingly colored tropical bird. Sadly, in those days national park boundaries were determined based on politics, rather than on conservation theory and they were far less effective in protecting the native species for which they established.

Though we had to stop our work earlier than we wanted for lack of funding, I am confident that the information we’ve gleaned from tracking these disparate species will enable decision makers to better protect the abundance of wildlife that calls the Peruvians Amazon home.

By Dr. George Powell
Dr. George Powell is a senior conservation scientist with WWF.